Introduce the concept of "Alternative Recordings"

[marcoroth]

Sometimes a talk doesn't get recorded or doesn't get published. But the "same" talk might have been given at another event. Instead of not showing a recording, we could link to that talk and/or embed the recording of the other event instead.

In the YAML file we could add another optional key for the talk. It could look like this for the José Valim Keynote at EuRuKo 2024:

- title: "Keynote: Livebook: where Web, AI, and Concurrency meet"
  raw_title: "Keynote: Livebook: where Web, AI, and Concurrency meet"
  event_name: EuRuKo 2024
  date: "2024-09-12"
  published_at: "2025-01-13"
  speakers:
    - José Valim
  description: "..."
  video_id: jose-valim-euruko-2024
  video_provider: not_recorded
  alternative_recordings:
    - title: "Livebook & Elixir: Where AI, Web & Concurrency Meet"
      event_name: "YOW. 2023"
      date: "2023-12-08"
      video_provider: youtube
      video_id: "pas9WdWIBHs"
      external_url: https://yowcon.com/sydney-2023/sessions/2758/livebook-and-elixir-where-ai-web-and-concurrency-meet

[adrienpoly]

assuming we get the embeddings done and display similar talks using those embeddings, I wonder if in this particular case we would be able to display automatically the talk "Livebook & Elixir: Where AI, Web & Concurrency Meet" and if this could not be a more generic solution for this particular case?

[marcoroth]

Ideally this feature would tie into this pull request here: #299 or this issue here: #236